Pressure still header



s. H. EDWARDS PRESSURE STILL HEADER Original Filed June 26, 1931 2 Sheets-s 1 Jan. 7, 1936. s. H. EDWARDS PRESSURE STILL HEADER 2 Sheets-Sheet 2 Original Filed June 26, 1931 Patented Jan. 7, 1936 PATENT OFFICE PRESSURE STILL HEADER Samuel H. Edwards, Richmond, OaliL, assignor to Standard Oil Company or California, San Francisco, Calif., a corporation of Delaware Original application June 26, 1931, Serial No.

547,006, now Patent No. 1,948,028, dated February 20, 1934. Divided and this application January 10, 1934, Serial No. 706,063

6Claims. (01.285-20) This invention relates to return bends, or headers, as they are commonly called, for mechanically joining and providing a fluid connection between the ends of two parallel tubes,

or pipes. It is particularly adapted foruse in water tube boilers, oil stills, and similar apparatus in which the tubes are numerous-are positioned close together, and must withstand high working pressures and temperatures.

An object of the invention is to provide a header construction of desirable mechanical and bydraulic characteristics, thatis, a header that is light, strong, heat resistant, and that has a smooth internal bore at least as large as the bore of the tubing iteonnects.

Another object is to provide a header that can be readily attached and removed even when used on tubes that are crowded very close together.

Another object is to provide a header that can be readily and cheaplymanufactured.

Present headers and return bends are 01' many types, but those most generally used consist either of a heavy cast steel body swaged to the tubes to be joined, or of flanged steel construction adapted to be attachedby numerous bolts to flanges on the ends of the tubes. The first type is heavy and is only adapted to bemade by casting, which, with the alloy steels required to prevent corrosion, is expensive to make, as the greater proportion of the castings poured is defective and must be rejected. Furthermore, the hydraulic characteristics of headers 01 this type are usually poor, and they may cause a large pressure drop. In case of injury to one tube, both tubes must usuallybe cut or burned out of the header and both tubes are usually destroyed during the removing process. The flange type is unsatisfactory chiefly because it is very bulky, which prevents the close nesting of the tubes.

factory features of the headers described would seem to be to provide a steel return band adapted ing sumcient force to the screw holding means to make the compression joint between the tubing and the header tight under the high pressure and temperatures under which they may be used. In

accordance with the present invention, this diiliculty has been overcome by uniting the header to the tubing with an elongated internally threaded nut provided with gear teeth around its outer circumference, and then devising a wrench A simple expedient to eliminate the unsatiscomprising a plurality of gears adapted to fit about and engage with the teeth on the nut whereby turning torque is applied to the nut at a plurality of points about its circumference. By a suitable gear reduction, the wrench multiplies 5 I the power applied to the nut so that an effective torque can be obtained of suflicient magnitude to produce a leak proof joint. It will be apparentthat this type of connection is not limited in its application to return bends alone, but can also be used with elbows and other types of joints of that nature, where a fitting is to be attached to a tube.

This is a division of my application Serial No. 547,006, filed June 26th, 1931, which issued February 20, 1934 as Patent No. 1,948,028.

Referring to the drawings:

Fig. 1 is a view partly in cross section showing a pair of tubes united by a header in accordance with my invention;

Fig. 2 is an end view of the header-shown in Fig. 1; Fig. 3 is a view showing the wrench applied to a header;

Fig. 4 is an end view of the wrench partly in section; and

Figs. 5 and 6 are sectional and end views, .respectively, 01 an element of the header construction shown in Fig. 1.

Referring to Fig. 1, two adjacent parallel tubes i are shown connected by a header 2. The open ends of header 2 are juxtaposed to the ends of tubes I, and may be sealed thereto by means of a gasket 3. The end of the header, may be formed into a tongue l2, and the end of pipe I may be grooved to receive the tongue as shown, but this construction is optional and flat surfaces may be substituted. Various well known forms of contact faces requiring no gasket may also be used.

The tubes l, which may be of alloy steel, are

as shown at 4, and are provided with an outer circumferential groove, or recess, 5 in which are fitted intemallyflanged steel retaining rings 6. The rings I are split into two halves as shown in Figs. 5 and 6, so that that they may be readily inserted in the grooves 5. Surrounding both tube I and split retaining ring 6, is an elongated cylindrical steel nut I which has an inwardly projecting flange I at one end forming a shoulder 50 resting against the retaining ring I. The upper internal portion of'nut 'I is provided with screw threads 9 which cooperate with similar threads" on the outer circumference of the end portion l0 oi header 2. The threads used to unite these 55 g 40. upset, or thickened internally adjacent their ends parts may b e of any desired type, but I have i found the Acme form particularly suitable in this i oonstruction. The inner diameter of the portion of nut] immediately above the shoulder 8 is such as to flt snugly about the retaining ring G and preventthe shoulder I I of J the ring escaping from the groove on the pipe i. The header 2, nut 1, split ring a and tube I preferably should-be constructed of similar metal in order that their coefllcient of expansion under temperature changes shall be the same. I- have found a material known in the trade as'KA2S chromium nickel iron alloy to be satisfactory for oil-still use; The header 2 maybe forged in one piece or may be made from a return bend portion ll of alloy steel electrically or autogenously welded as at 42 to a forged steel tubular section 43. Shoulders 28 having a bearing hole 25 are formed on the upper part of the header; 2. Their use will be explained later. In-pmembling'. the header, the nut I is first slipped over the end of pipe I then the two halves of the retaining ring 8 are insertedin the groove 5 and the nut I withdrawn toward the end of the tube as far as it will go, to hold the retaining ringsin position. The header 2 is then brought into position and the put, I threaded onto the shoulder III of the h a er." By tightening the nut I, the end I2 of. the header is brought against the end of pipe I so that the joint is sealed against. leakage. The eflicie'ncy of a joint of this yp depends, amongother things, upon the force v with which the We parts are held together. The force obtainable is usually limited by the torque 85 which can be, applied to. the nut "I. To makepossible the application of suflicient torque to nut I to produce a tight joint, the outer circumference of nut I is made cylindrical in shape and is providedwith gear teeth It (as shown to the best advantage in Fig. 2) to meshwith gears in a special wrench designed for use therewith.

As shown in Fig. 3, this wrench consists of a frame comprising an upper plate It and a lower plate II united by a U-shaped Joiningwall It. The lower plate I! has a portion cut out forming .an aperture ll, to permit it to slip over end i of the header 2and ntsnugly thereaboutr Rotatably mounted between the plates II and I! and equidistant from a central point, are a plurality of shafts II. These shafts extend through bushings II in the upper plate It and through bushings IS in the lower plate II,

Shoulders and 2| on the shafts bear against the ends of bushings II and I! to prevent longi-' tudinal motion of the shafts. 'Each shaft H has va pinion 2| with teeth formed therein adapted tomeshwiththeteethonthenut I andtheshafts I I are positioned about nut I so that the teeth on eachpinion 28. willmeshwlththeteeth II. A driving shaft 22 is rotatably supportedin a bushing 22 in, the top plate I, and,in use, is .supportedat itslower endby anextenslon 24 adapted to fltintobearing hole 25 in shoulder 2| on-header, v2. Mounted on shaft 22 between bushing 22 and the extension 2! is an elongated pinion'2l which with a plurality of gears ll, each of which ismoimted onand rigidly attachedto one of the shafts II. To enable all the gears 22 to mesh j with pinion .21, some of them are mounted diflerI- 7o ent'distancesfromtheplate ,sothattheyoverlap,asshownclearlyinl'lg ..3. Fig.4showshowallthesehrsilmeshwith the central pinion 2'I. I'he'frameof the wrench is so dimensionedthat driving shaft 22 is ooadal hdiacent tube 82 is'shown' tioned ta,w ta-m1,snot bes nsi .q e h M assert concentrically positioned with respect to the extended axis of nut I; therefore, it follows that when the wrench assembly is dropped over the end of the header so that shaft extension to fits into bearing 26, the pinions 28 fit about the nut I and mesh with the teeth it thereon; In the tightening operation, a wrench may be applied to the hexagonal end29 of driving shaft 22'and the shaft rotated.

The rotary motion of shaft 22 is transmitted 19 through pinion 2i and gears 38 to shafts iI, forcing them all to rotate in the same direction, which causes pinion 28 on each shaft ii to apply an equal turning moment to the nut I. Obviously, by the simultaneous application of force 15 to the nut at a plurality of points around its circumference, far greater force can be exerted without Injury thereto than if it were attempted to apply the. total force at one point. In addition, the gear train provides a substantial multiso pllcation of the force applied to shaft 22, since the pinion 21 on that shaft is of relatively small diameter compared with the diameter of gears 38 and the pinions 28 are of substantially smaller diameter than gears 38, and are usually smaller 25 than the nut I with which they engage.

' I It will be noted that since'there is an intermediate gear between shaft 22 and the nut I, the direction of rotation of shaft 22 and the nut I are the same, there being. two reversals of direction; that is,.clockwise rotation of the shaft 22 produces counterclockwise rotation of shafts II which in turn produce clockwise'rotation of the To protect workmen from possible injury, all light sheet metal guard 20 may be provided. It is attached to the upper plate II by screws II as indicated in Figure 3, and extends over the gears 28.

Inutilizin'g the assembling wrench,atube I fell)- tary motion thereto. The'rotation of shaft 22 rotates the gears ll in the reverse direction and since the frame bearingthe gears 38 is prevented from turning by the door plate I5 which fits I snuglyabout the header tube, the gears SI and 55 shafts II forced to turn in bearings I! and II and rotate the nut I by engagement between the teeth II-on the nut and the teeth onplnions 28.

- Obviously, to remove" a header, the wrench is applied in the same manner and shaft 22 turned in the reverse direction. After the nutsI are loosened, the header is bled by sliding nut I bach'thus permitting the removal of the split rings 6, after which thenut I may be withthe end of tube I, The tube is thus left free .and undaniaged for oleaning. 8 81118- rotation, or removal.

A particular advantage of the wrench is that the pinions a which cheese with ,the'nut 1 may I" be'madeofrelativelysmalldi v etersothatthe wrenchmaybeusedonverycl ers: thus in Fig.8, the header-attached to an just far away header-2w permit clear- 1 I aoaaeu ance between the pinion on shaft I I and teeth onthe nut 33 t header I4.

It should be noted that since the nut I screws onto the header 2, no undue torque or twisting strain is applied tothe tubes themselves; this is 1 advantageous since'such strains may tend to distort or injure the tubes either at the time of assembling the headers or while they are under the stresses caused by high pressures or temperation, wrench centering means on said bend oppoand a nut for said threaded portion provided site to and coaxial with said threaded portion with spaced projections thereon with which a wrench may be engaged for turning said nut.

2. A fitting for joining two adjacent tubes comprising a return bend having tangential threaded portions, centering means on said-bend opposite to and coaxial with said threaded portions and nuts for said threaded portions .provided with spaced projections thereon, whereby turning means for said nuts having complementary projections thereon will be centered on said fitting and engaged with the projections on said nuts to rotate the same.

a nut for said threadedportion having symmetrically spaced projections thereon.

4. A return bend fitting tor connecting two adjacent tubes comprising a member having a U bend passage therethrough and having a threaded end, wrench centering means on the arcuate portion of said member coaxial with said thread? 5 ed end, and a nut for said threaded end, said nut having symmetrically spaced projections thereon for engagement by a wrench; and having means for rotatably eng ing one of said tubes to clamp the tube against the end of the fitting when the 1 nut is screwedonto the fitting.

5. A fitting for connecting two adjacent tubes comprising an arcuate bend member having a threaded end portion, wrench centering means on said bend member coaxial with said threaded l5 portion, and a nut for said threaded portion having spaced projections thereon for engagement by a wrench, said nut having means for engaging a tube to clamp the same against the end of said arcuate bend when said nut is screwed onto said 20 fitting.

6. A return bend'fitting for connecting two adjacent tubes comprising a member having an arcuate passage therethrough and having a threaded end, wrench centering means on said 25 member opposite said threaded end and coaxial therewith, and a nut for said threaded end having spaced projections thereon for engagement by a wrench, said nut having means for engag-' ing one of said tubes to clamp the same against the end of said fitting when said nut is screwed thereon.

SAMUEL H. EDWARDS. 

